Magnetic data storage devices generally include magnetic recording heads, commonly referred to as transducing heads, which can detect and modify the magnetic properties of a magnetic storage medium to store data.
Air-bearing sliders can be used in magnetic data storage devices to appropriately position a transducing head above a rotating magnetic disc. During operation, the disc typically rotates at high speeds, which can generate a stream of air flow immediately adjacent to the flat surface of the disc. This stream of air acts upon a lower air-bearing surface of the air-bearing face of the slider and can generate a force directing the slider away from the disc and against a load beam causing the slider to “fly” a small distance above the disc.
A prior art magnetic recording apparatus is shown in FIG. 1. The apparatus 10 is commonly referred to as a hard disc drive (HDD) and includes a slider 14 that flies above a disc 11 by using air as a lubricant. Referring to FIG. 1, a disc 11 is placed on a spindle motor 12 that can rotate and a negative pressure air-lubricated bearing slider 14 is attached at a suspension 15 to correspond to the magnetic disc 11. The negative pressure air-lubricated bearing slider 14 can be moved (as indicated by the arrow and dashed lines) by an actuator 16 which pivots so that the slider 14 moves to a desired position on a track 13 of the disc 11. As shown, the disc 11 used as a recording medium has a circular shape and different information can be recorded on each track 13. In general, to obtain desired information, the slider 14 moves in search of a corresponding track on the disc 11. Disc 11 can have a magnetic layer that is susceptible to physical and/or chemical damage. To help mitigate such damage, such a disc often has a coating such as Diamond-like Carbon (DLC) as an overcoat to help protect the magnetic layer from physically and/or chemically induced damage. Discs such as disc 11 often have one or more lubricants on the top surface thereof to help reduce friction and corrosion.
FIG. 2 shows a schematic diagram of prior art air-bearing slider body 120 of a magnetic recording head, which includes air-bearing face 122 defined by leading edge 120a, trailing edge 120b, and two side edges 120c connecting the leading and trailing edges. Air-bearing slider 120 also includes transducing head 124. As shown in FIG. 2, transducing head 124 is arranged toward trailing edge 120b of slider body 120. Air-bearing face 122 can be designed to control the aerodynamic performance of slider body 120 as it flies over a rotating magnetic disc. As shown, air-bearing face 122 includes structural features such as rails, lands, ramps, depressions and the like that are typically designed to maximize the pressure on air-bearing surfaces of the air-bearing face created by the stream of air flowing between face 122 and the disc near transducer 124. Causing pressure at transducer 124 to be relatively high can help increase the stiffness of the suspension assembly (not shown) of the magnetic recording head at transducer 124. Increasing the stiffness can cause the suspension assembly, e.g. an actuator arm, and thereby the recording head, to be less subject to system vibration during operation, which in turn can minimize fly height sensitivity to manufacturing variation, environmental factors, and disk roughness.
As magnetic disc storage systems are designed for greater and greater storage capacities, the aerial density of magnetic discs is generally increasing such that the air-bearing gap between the transducer carried by the slider and the rotating magnetic disc is oftentimes reduced, which in turn can result in operating the air-bearing slider at ultra-low fly heights.
Unfortunately, a reduction in flying height can result in a variety of undue interactions between the slider (especially the trailing edge of the slider) and disc. For example, lubricant that is typically provided on a disc may result in interference among a slider and the lubricant on the disc to an undue degree. One problem with lubricant and undue interactions among a slider and a disc is described with respect to FIGS. 3 and 4. As shown in FIGS. 3 and 4, a slider body 230 includes an air bearing face 215 having a leading edge 225 and a trailing edge 250. Slider body 230 also includes a first side face 235, a second side face (not shown), and trailing edge face 270. During operation, lubricant 220 (which sometimes includes contaminants) can be transferred to slider body 230 from disc 210 during operation of a disc drive and form droplets 225 on air bearing face 215. After lubricant 220 transfers to air bearing face 215, it tends to migrate on the air bearing face 215 due to, e.g., underlying shear and pressure gradient forces represented by streamlines 240. The droplets 225 of lubrication tend to migrate toward the trailing edge 250 of the slider 230. Near trailing edge 250, the lubrication tends to accumulate and form larger droplets 226 of lubrication. This may result in undesirable changes to the mean targeted head-media clearance and thereby affect drive performance to an undue degree. Additionally, droplets 226 can stick on to the slider body 230 near trailing edge 250 and grow in size until they eventually drop off under the action of some triggering force (such as during a shock event). The droplets of lubrication that are transferred back to disc 210 can interact with the slider 230 under certain circumstances to an undue degree (e.g., reduce head-disc clearance, cause large head-media spacing variation, and the like). Such interaction can in turn result in an excitation of the slider that may cause weak writes and/or read-write errors.
Accordingly, there is a need to manage lubricant that has transferred from a disc onto a slider body.